Cyclone Codes

We introduce Cyclone codes which are rateless erasure resilient codes. They combine Pair codes with Luby Transform (LT) codes by computing a code symbol from a random set of data symbols using bitwise XOR and cyclic shift operations. The number of data symbols is chosen according to the Robust Soliton distribution. XOR and cyclic shift operations establish a unitary commutative ring if data symbols have a length of $p-1$ bits, for some prime number $p$. We consider the graph given by code symbols combining two data symbols. If $n/2$ such random pairs are given for $n$ data symbols, then a giant component appears, which can be resolved in linear time. We can extend Cyclone codes to data symbols of arbitrary even length, provided the Goldbach conjecture holds. Applying results for this giant component, it follows that Cyclone codes have the same encoding and decoding time complexity as LT codes, while the overhead is upper-bounded by those of LT codes. Simulations indicate that Cyclone codes significantly decreases the overhead of extra coding symbols

Computing Shortest Paths in Series-Parallel Graphs in Logarithmic Space

Series-parallel graphs, which are built by repeatedly applying series or parallel composition operations to paths, play an important role in computer science as they model the flow of information in many types of programs. For directed series-parallel graphs, we study the problem of finding a shortest path between two given vertices. Our main result is that we can find such a path in logarithmic space, which shows that the distance problem for series-parallel graphs is L-complete. Previously, it was known that one can compute some path in logarithmic space; but for other graph types, like undirected graphs or tournament graphs, constructing some path between given vertices is possible in logarithmic space while constructing a shortest path is NL-complete

Private Computation: k-Connected versus 1-Connected Networks

We study the role of connectivity of communication networks in private computations under information theoretical settings in the honest-but-curious model. We show that some functions can be 1-privately computed even if the underlying network is 1-connected but not 2-connected. Then we give a complete characterisation of non-degenerate functions that can be 1-privately computed on non-2-connected networks. Furthermore, we present a technique for simulating 1-private protocols that work on arbitrary (complete) networks on k-connected networks. For this simulation, at most $(1 - k/(n - 1)) \cdot L$ additional random bits are needed, where L is the number of bits exchanged in the original protocol and n is the number of players. Finally, we give matching lower and upper bounds for the number of random bits needed to compute the parity function on k-connected networks 1-privately, namely $\lceil (n - 2)/(k - 1) \rceil - 1$ random bits for networks consisting of n player

Cross-calibration of the Siemens mMR:easily acquired accurate PET phantom measurements, long-term stability and reproducibility

BACKGROUND: We present a quick and easy method to perform quantitatively accurate PET scans of typical water-filled PET plastic shell phantoms on the Siemens Biograph mMR PET/MR system. We perform regular cross-calibrations (Xcal) of our PET systems, including the PET/MR, using a Siemens mCT water phantom. LONG-TERM STABILITY: The mMR calibration stability was evaluated over a 3-year period where 54 cross-calibrations were acquired, showing that the mMR on average underestimated the concentration by 16 %, consistently due to the use of MR-based μ-maps. The mMR produced the narrowest calibration ratio range with the lowest standard deviation, implying it is the most stable of the six systems in the study over a 3-year period. MMR ACCURACY WITH PREDEFINED μ-MAPS: With the latest mMR software version, VB20P, it is possible to utilize predefined phantom μ-maps. We evaluated both the system-integrated, predefined μ-map of the long mMR water phantom and our own user-defined CT-based μ-map of the mCT water phantom, which is used for cross-calibration. For seven scans, which were reconstructed with correctly segmented μ-maps, the mMR produced cross-calibration ratios of 1.00–1.02, well within the acceptance range [0.95–1.05], showing high accuracy. CONCLUSIONS: The mMR is the most stable PET system in this study, and the mean underestimation is no longer an issue with the easily accessible μ-map, which resulted in correct cross-calibration ratios in all seven tests. We will share the user-defined μ-map of the mCT phantom and the protocol with interested mMR users

Intra- and inter-cell interference investigations for broadband radio access systems above 10 GHz, Journal of Telecommunications and Information Technology, 2001, nr 2

Local multipoint distribution systems (LMDS) operating above 10 GHz have a large bandwidth (2–3 GHz) but a very limited range. These systems can provide coverage to a few kilometers only. The size of the macro cells illuminated by the base stations, where line of sight (LOS) exists, is 1 to 6 km. To provide coverage to customers where LOS is not possible, repeaters or passive reflectors may be used. In this paper we present first results of reflection measurements at 42 GHz, and based on that, simple multipath studies, taking into account the beam width of the antennas of both, transmitter and receiver. Secondly, LOS cochannel and adjacent channel interference are assessed for cellular LMDS networks. As suggested in the CRABS report, the maximal spectral efficiency can be obtained with a dual frequency and polarization reuse plan. This frequency and polarization reuse leads to interference. In this paper we have first calculated the cochannel interference (CCI) and the adjacent channel interference (ACI) due to the frequency/polarization reuse schemes suggested in the CRABS report. The effects of the variation of the half power beam width (HPBW) of the receiver, the time percentage parameter p, and the cell radius on C/I are also reported. In the latter part of the paper we propose a simple interference reduction technique based on re-orientation of the receiver antennas. We have also explored the possibility of using trellis coded modulation (TCM) for reducing interference levels. Initial results have been found to be quite encouraging

The German National Registry of Primary Immunodeficiencies (2012-2017)

Introduction: The German PID-NET registry was founded in 2009, serving as the first national registry of patients with primary immunodeficiencies (PID) in Germany. It is part of the European Society for Immunodeficiencies (ESID) registry. The primary purpose of the registry is to gather data on the epidemiology, diagnostic delay, diagnosis, and treatment of PIDs. Methods: Clinical and laboratory data was collected from 2,453 patients from 36 German PID centres in an online registry. Data was analysed with the software Stata® and Excel. Results: The minimum prevalence of PID in Germany is 2.72 per 100,000 inhabitants. Among patients aged 1–25, there was a clear predominance of males. The median age of living patients ranged between 7 and 40 years, depending on the respective PID. Predominantly antibody disorders were the most prevalent group with 57% of all 2,453 PID patients (including 728 CVID patients). A gene defect was identified in 36% of patients. Familial cases were observed in 21% of patients. The age of onset for presenting symptoms ranged from birth to late adulthood (range 0–88 years). Presenting symptoms comprised infections (74%) and immune dysregulation (22%). Ninety-three patients were diagnosed without prior clinical symptoms. Regarding the general and clinical diagnostic delay, no PID had undergone a slight decrease within the last decade. However, both, SCID and hyper IgE- syndrome showed a substantial improvement in shortening the time between onset of symptoms and genetic diagnosis. Regarding treatment, 49% of all patients received immunoglobulin G (IgG) substitution (70%—subcutaneous; 29%—intravenous; 1%—unknown). Three-hundred patients underwent at least one hematopoietic stem cell transplantation (HSCT). Five patients had gene therapy. Conclusion: The German PID-NET registry is a precious tool for physicians, researchers, the pharmaceutical industry, politicians, and ultimately the patients, for whom the outcomes will eventually lead to a more timely diagnosis and better treatment

The Average Time Complexity to Compute Prefix Functions in Processor Networks

We analyze the average time complexity of evaluating all prefixes of an input vector over a given algebraic structure h\Sigma; . As a computational model networks of finite controls are used and a complexity measure for the average delay of such networks is introduced. Based on this notion, we then define the average case complexity of a computational problem for arbitrary strictly positive input distributions. We give a complete characterization of the average complexity of prefix functions with respect to the underlying algebraic structure h\Sigma; \Omega\Gamma resp. the corresponding Moore-machine M . By considering a related reachability problem for finite automata it is shown that the complexity only depends on two properties of M , called confluence and diffluence. We prove optimal lower bounds for the average case complexity. Furthermore, a network design is presented that achieves the optimal delay for all prefix functions and all inputs of a given length while keeping the netw..

Privacy-aware access control for video data in intelligent surveillance systems

Surveillance systems became powerful. Objects can be identied and intelligent surveillance services can generate events when a specific situation occurs. Such surveillance services can be organized in a Service Oriented Architecture (SOA) to fulfill surveillance tasks for specific purposes. Therefore the services process information on a high level, e.g., just the position of an object. Video data is still required to visualize a situation to an operator and is required as evidence in court. Processing of personal related and sensitive information threatens privacy. To protect the user and to be compliant with legal requirements it must be ensured that sensitive information can only be processed for a defined propose by specific users or services. This work proposes an architecture for Access Control that enforces the separation of data between different surveillance tasks. Access controls are enforced at different levels: for the users starting the tasks, for the services within the tasks processing data stored in central store or calculated by other services and for sensor related services that extract information out of the raw data and provide them